<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>
<script>
    var socket;
    // 判断当前浏览器是否支持websocket编程
    if (window.WebSocket) {
        // go on
        socket = new WebSocket("ws://localhost:7000/hello");
        // 相当于channelRead0，收到服务器回送的消息
        socket.onmessage = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + ev.data;
        }
        // 相当于连接开启（感知到连接开启）
        socket.onopen = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = "连接开启了...";
        }
        // 相当于连接关闭（感知到连接关闭）
        socket.onclose = function (ev) {
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + "连接关闭了...";
        }
        // 相当于连接异常
        socket.onerror = function (ev){
            var rt = document.getElementById("responseText");
            rt.value = rt.value + "\n" + "连接异常了...";
        }
    } else {
        alert("当前浏览器不支持websocket")
    }

    // 发送消息到服务器
    function send(message){
        // websocket对象没有创建好
        if (!window.socket){
            return ;
        }
        // 判断websocket是打开的状态
        if (socket.readyState == WebSocket.OPEN){
            // 通过socket发送消息
            socket.send(message)
        }else{
            alert("连接未开启")
        }
    }
</script>
<form onsubmit="return false">
    <textarea name="message" style="height: 300px;width: 300px"></textarea>
    <input type="button" value="发送消息" onclick="send(this.form.message.value)">
    <textarea id="responseText" style="height: 300px;width: 300px"></textarea>
    <input type="button" value="清空内容" onclick="document.getElementById('responseText').value=''">
</form>
</body>
</html>